Passivation of semiconductor surfaces with low-energy hydrogen

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In this work, we have investigated on thermally or remote plasma excited hydrogen induced surface reaction and effects on a surface electric structure of silicon related semiconductors.First, we tried to remove fluorine adsorbates on silicon by atomic hydrogen (or deuterium) exposure at low substrate temperature. From in-situ Auger electron analysis, it is found that the fluorine adsorbates are completely removed at 200ﾟC through this process. Moreover, we confirmed the hydrogen passivated surface from TDS (thermally stimulated desorption spectroscopy). During the fluorine removal process, we have estimated the SiD2F2 molecules as main reaction products in the initial stage , and the SiDF molecules as those decreasing the surface density of the fluorine atoms.Second, we have deposited tungsten films onto Si and SiO2 substrates from WF6 gas with plasma excited hydrogen below 350ﾟC.Increasing the supply of the excited hydrogen, the tungsten films grow non-selectively, the reaction order changes, and the resistivity of the deposited films decreases. These phenomena are due to the activation of the extraction of fluorine atoms from WF6 and the surfaces.Third, the effects of hydrogenation on the electric characteristics of undoped polycrystalline silicon films have been investigated. We propose a current conduction model including both a conventional band conductive component and a hopping conductive component along the grain boundary. This model can explain the tendency of the variation of the resistivity of the films and its activation energy induced by the hydrogenation.